LOL. I mean, I really sympathise with you, because my dd is exactly like this! I don't know if it is normal or not, but it is normal for her, and we've got used to it, (although it is a relief to hear of others with these obsessions). She is now 3 years 6 months now, and is starting to get a little less obsessive, although she still likes to take random things with her out and about, rather than one favourite.
When she was around 18 months or so (I forget now - but this obsession lasted a long time) she used to take a foot-long batmobile to bed with her, and also out in her push-chair - I found it unbearable at the time as it was such a large, un-cuddly toy, and she insisted holding it whilst being put to bed. She doesn't really like cuddly things much, can't stand dollies and things which resemble humans too accurately (she likes Morph-type things though). She had a very good pincer grip from a young age, and would love to hold small, hard objects, and stopped mouthing things very early.
I sort of missed the batmobile when she graduated to a single tiny block of lego, either white or yellow which she would hold in her hand as a bed-time toy, and would get very upset if she lost it at night. Since then, it's the same as your ds, LittleOneMum - a succession of usually tiny, random objects which need to be taken to bed, and heaven forbid if she left the house without them or lost them at night.
However, I think she started to get better with the obsessions a couple of months ago though. For instance, she has improved with her choice of bed-time toy, now that she can understand better. She takes her beaker to bed with her and is allowed to select one bed-time toy - we tell her if it is suitable or unsuitable as a bed-time toy (our decision is accepted by her, thank the lord). For a laugh the other day, my dh suggested that she took a small weeble-sized dolly to bed, she said "no" straight away, but then he offered a long flat strip of lego, she accepted immediately. She doesn't now get upset if she loses the toy at night.
I, too, am interested hear of others who have had quirky toddlers like this, and what they are like as older children.